1. Field of the Invention
The present invention is directed to a cryogenic storage vessel wherein the inner storage tank is suspended from the outer storage tank by means of a compound strap.
2. Description of the Prior Art
Many exemplary straps for suspending an inner tank from an outer tank are illustrated in the prior art. For example, the patent issued to Heylandt, U.S. Pat. No. 1,866,517, discloses a double wall storage container having suspension chains with sections of low thermal leakage to support the inner container shell. The patent issued to Wexler et al, U.S. Pat. No. 2,722,336, discloses a spaced wall arrangement to store liquefied gases wherein one smaller inside container is supported and spaced within a larger outer container by a plurality of spacers having heat insulation properties for thermally insulating the liquefied gas stored within the inside container.
The patents issued to Berner et al, U.S. Pat. No. 3,230,726, and Hoffman et al, U.S. Pat. No. 3,274,788, disclose double-walled thermally-insulated containers wherein the inner product container is supported relative to the outer insulating container by means of a low thermal conductivity material to minimize heat leakage.
The Bridges patent, U.S. Pat. No. 3,623,626, discloses a system for supporting product tanks housed within the hold of a ship. The supporting elements comprise arms or links connected to the product tank and to the structure of the ship which vary in accordance with a predetermined straight-line contraction and expansion of the tank.
In addition to the prior art discussed above, several other methods have been used to support the inner shell of a cryogenic storage vessel from the inner surface of the outer shell. These methods used highly porous low conductivity material such as woven fiberglass or balsa wood to support the inner shell.
The support means for connecting an inner container to an outer container disclosed in the prior art suffers from disadvantages which are solved by the compound strap of the present invention. The present invention sets forth a novel combination of a compound strap consisting of two or more links of different thicknesses. More particularly, the compound strap of the present invention is used in a cryogenic storage vessel to support an inner storage tank from an outer storage tank. The compound strap of the present invention is preferably made of a fiberglass epoxy resin material which is designed to minimize heat leakage from the outer storage tank to the inner storage tank.